1. Field of the Invention
This invention relates to thiophene compound copolymers and a method for the production thereof. More particularly, this invention relates to copolymers of 3-ndodecylthiophene and 3-methylthiophene, copolymer compositions resulting from doping the copolymers with a dopant, and an electrochemical method for the production thereof. These copolymers and copolymer compositions are used, depending on their qualities, for various electronic parts, electrodes, sensors, photoelectric conversion devices, various parts and devices, and the like.
2. Prior Art Statement
In recent years, the remarkable technical growth in the electronic industry has promoted development of materials possessing new and excellent electric functions. In the field of polymer chemistry, materials possessing various electric properties have been discovered and many of them have already found utility in practical applications. Efforts are being continued in search of materials possessing still more desirable electric properties. Particularly, organic electroconductive materials possessing electroconductivity are extensively usable for various electronic parts, electrodes, sensors, and photoelectric conversion devices, for example. Thus, research is being actively promoted for the development of organic electroconductive materials possessing outstanding characteristic properties.
The organic electroconductive materials which have been known in the art include those which are obtained by adding dopants to polyacetylene, polythiophene, poly(p-phenylene), polyphenylene sulfide, and polypyrrol and additionally include organometallic polymers. These organic electroconductive materials, however, have little practical value as polymer materials because they are insoluble in various solvents and are extremely difficult to mold because of their infusibility.
One of the present inventors continued a study on thiophene compound polymers. The inventions resulting from this study have been granted U.S. Pat. Nos. 4,691,005, 4,737,557, 4,877,852. For the divisional application of U.S. Pat. No. 4,877,852, U.S. Pat. application Ser. No. 07/306,581, a Notice of Allowance has already been received.
As thiophene type polymers, poly-(2,5thienylene) and poly-[2,5-(3-methylthienylene)]which are obtained respectively by electrochemically polymerizing thiophene and 3-methylthiophene and then electrochemically reducing the resultant polymers have been known to the art. These polymers, however, have little practical value as polymer materials because they are insoluble in various solvents and are extremely difficult to mold because of their infusibility.
Polymer compositions obtained by electrochemically polymerizing 3-longchain alkylthiophenes possessing a longchain alkyl group (having 6 to 12 carbon atoms) at the 3 position of the thiophene ring ["Synthetic Metal", Vol. 18, pages 229-232 (1987)]and homopolymers of poly-[2,5-(3-longchain alkyl thienylenes)]obtained by electrochemically reducing the polymer compositions have been known to the art ["Journal of Chemical Society Chemical Communication", pages 837 to 874 (1986)]. Unless these polymer compositions are subjected to drawing or other such processing they exhibit an electrical conductivity of only 100 S/cm and as such are not satisfactory as materials for organic electroconductive devices or as materials for applications requiring various electric and electronic functions.
One object of this invention is to provide a novel electroconductive copolymer composition which possesses excellent electroconductivity, excels in moldability, and enjoys high practical value as by permitting economic production.
Another object of this invention is to provide a novel thiophene copolymer with a high degree of polymerization which is soluble in solvents, excellent in moldability, and useful as materials for parts fitting various applications and as polymer materials for applications of various electric and electronic functions.